I'm 70. At 60 I had blood in my urine for two days. Ive, cystoscopy, prostate tests normal. Month ago blood in urine three times. Possible causes?

Many causes. Sounds like the tests you had were 11 yrs.ago.There are many causes of blood in the urine. You need radiographic study:CT-IVP as an initial study to find the cause of bleeding.Listing all causes is no help but could be bladder tumor,prostate bleeding,kidney tumor,renal pelvic tumor...Please make sure you get tested.Best wishes.
Hematuria. Bladder infections or prostate infections can show this. And, then there are a number of other possible causes. Your physician may want to do more testing now at age 70 than they did ten years ago.